Para chloro ortho cresol carboxylic acid



Patented Feb. 23, 1932 UNITED STATES PATENT OFFICE LEOPOLD LASKA AND OSKAR EALLER, OF OFFENBACH-ON-THE-MAIN, GERMANY, AB-

SIGNORS T0 GENERAL ANILINE WORKS, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE PARA. CHLORO ORTHO CRESOL CABIBOXYLIC ACID No Drawing. Application filed May 22, 1930, Serial No. 454,824, and in Germany May28, 1929;

Our present invention relates to parachloro-ortho-cresol-carboxylic acid and to a process of making same.

This process consists in heating with car- ,bonic acid under pressure an alkali metal salt of 1-methyl-l-chloro-2-hydroXy-benzene.

This phenol has several positions unoccupied and therefore several isomer carboxylic acids were to be expected. Nevertheless the uniform formation of a single carboxylic acid has been proved.

Since this carboxylic acid exhibits an intense violettish coloration when mixed with ferric chloride, the carboxylic group is proved to have entered into the free orthoposition relating to the hydroxyroup. Our process represents the rare case of the smooth formation of a 1.2.3-4-substituted benzene. The acid corresponds probably to the formula OH COOH It is a valuable intermediate product for the productionof dyestuffs.

In order to further illustrate our invention the following example is given, the parts being by weight and all temperatures in centigrade degrees, but it is however to be understood, that our invention is not limited to the particular reacting conditions mentioned t erein.

Ewample 1425 parts of 1-methyl-4-chloro -2-h droxybenzene are dissolved in 416 parts 0 caustic soda of 96% and 3000 parts of water in an autoclave provided with a stirrer and the water is distilled off, finally in vacuo, until the mass becomes entirely dry. Into the cold reaction mass carbonic acid is introduced until a pressure of 10 atmospheres and the Whole is heated to 150 for 10 hours. The cold mass is dissolved in hot water. From the filtered solution the 1-methyl4-chloro-2- hydroxy-benzene-3-carboxylic acid is precipitated by means of hydrochloric acid. For

further purification it is dissolved in sodium CH CODE which compound represents when recrystallized from benzene small needles melting at 155 and yields when dissolved in alcohol a violet coloration after the addition of a dilute solution of ferric chloride.

In testimony whereof, we aflix our signatures. v

LEOPOLD LASKA. OSKA R HALLER. 

